More closely follow compiler naming patterns.

src/Compilers/CSharp/Portable/CSharpCodeAnalysis.csproj

@@ -286,7 +286,7 @@
     <Compile Include="DocumentationComments\PEDocumentationCommentUtils.cs" />
     <Compile Include="DocumentationComments\SourceDocumentationCommentUtils.cs" />
     <Compile Include="Emitter\EditAndContinue\CSharpDefinitionMap.cs" />
-    <Compile Include="Emitter\EditAndContinue\CSharpLambdaSyntaxHelper.cs" />
+    <Compile Include="Emitter\EditAndContinue\CSharpLambdaSyntaxFacts.cs" />
     <Compile Include="Emitter\EditAndContinue\EmitHelpers.cs" />
     <Compile Include="Emitter\EditAndContinue\PEDeltaAssemblyBuilder.cs" />
     <Compile Include="Emitter\EditAndContinue\CSharpSymbolMatcher.cs" />

src/Compilers/CSharp/Portable/Emitter/EditAndContinue/CSharpDefinitionMap.cs

@@ -35,10 +35,7 @@ internal sealed partial class CSharpDefinitionMap : DefinitionMap<CSharpSymbolMa
 
         internal override CommonMessageProvider MessageProvider => CSharp.MessageProvider.Instance;
 
-        protected override ILambdaSyntaxHelper GetLambdaSyntaxHelper()
-        {
-            return CSharpLambdaSyntaxHelper.Instance;
-        }
+        protected override LambdaSyntaxFacts GetLambdaSyntaxFacts() => CSharpLambdaSyntaxFacts.Instance;
 
         internal bool TryGetAnonymousTypeName(NamedTypeSymbol template, out string name, out int index)
         {

src/Compilers/CSharp/Portable/Emitter/EditAndContinue/CSharpLambdaSyntaxHelper.cs → src/Compilers/CSharp/Portable/Emitter/EditAndContinue/CSharpLambdaSyntaxFacts.cs

@@ -4,20 +4,20 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.Emit
 {
-    internal class CSharpLambdaSyntaxHelper : ILambdaSyntaxHelper
+    internal class CSharpLambdaSyntaxFacts : LambdaSyntaxFacts
     {
-        public static readonly ILambdaSyntaxHelper Instance = new CSharpLambdaSyntaxHelper();
+        public static readonly LambdaSyntaxFacts Instance = new CSharpLambdaSyntaxFacts();
 
-        private CSharpLambdaSyntaxHelper()
+        private CSharpLambdaSyntaxFacts()
         {
         }
 
-        public SyntaxNode GetLambda(SyntaxNode lambdaOrLambdaBodySyntax)
+        public override SyntaxNode GetLambda(SyntaxNode lambdaOrLambdaBodySyntax)
         {
             return LambdaUtilities.GetLambda(lambdaOrLambdaBodySyntax);
         }
 
-        public SyntaxNode TryGetCorrespondingLambdaBody(
+        public override SyntaxNode TryGetCorrespondingLambdaBody(
             SyntaxNode previousLambdaSyntax,
             SyntaxNode lambdaOrLambdaBodySyntax)
         {

src/Compilers/Core/Portable/CodeAnalysis.csproj

@@ -53,7 +53,7 @@
     <Compile Include="CodeGen\ItemTokenMap.cs" />
     <Compile Include="Emit\DebugDocumentsBuilder.cs" />
     <Compile Include="EmbeddedText.cs" />
-    <Compile Include="Emit\EditAndContinue\ILambdaHelper.cs" />
+    <Compile Include="Emit\EditAndContinue\LambdaSyntaxFacts.cs" />
     <Compile Include="InternalUtilities\EncodingExtensions.cs" />
     <Compile Include="InternalUtilities\BlobBuildingStream.cs" />
     <Compile Include="GlobalSuppressions.cs" />

src/Compilers/Core/Portable/Emit/EditAndContinue/DefinitionMap.cs

@@ -315,10 +315,10 @@ internal VariableSlotAllocator TryCreateVariableSlotAllocator(EmitBaseline basel
                 hoistedLocalMap,
                 awaiterSlotCount,
                 awaiterMap,
-                GetLambdaSyntaxHelper());
+                GetLambdaSyntaxFacts());
         }
 
-        protected abstract ILambdaSyntaxHelper GetLambdaSyntaxHelper();
+        protected abstract LambdaSyntaxFacts GetLambdaSyntaxFacts();
 
         private void ReportMissingStateMachineAttribute(DiagnosticBag diagnostics, IMethodSymbolInternal method, string stateMachineAttributeFullName)
         {

src/Compilers/Core/Portable/Emit/EditAndContinue/EncVariableSlotAllocator.cs

@@ -36,7 +36,7 @@ internal sealed class EncVariableSlotAllocator : VariableSlotAllocator
         private readonly IReadOnlyDictionary<int, KeyValuePair<DebugId, int>> _lambdaMapOpt; // SyntaxOffset -> (Lambda Id, Closure Ordinal)
         private readonly IReadOnlyDictionary<int, DebugId> _closureMapOpt; // SyntaxOffset -> Id
 
-        private readonly ILambdaSyntaxHelper _lambdaSyntaxHelper;
+        private readonly LambdaSyntaxFacts _lambdaSyntaxFacts;
 
         public EncVariableSlotAllocator(
             SymbolMatcher symbolMap,
@@ -51,7 +51,7 @@ internal sealed class EncVariableSlotAllocator : VariableSlotAllocator
             IReadOnlyDictionary<EncHoistedLocalInfo, int> hoistedLocalSlotsOpt,
             int awaiterCount,
             IReadOnlyDictionary<Cci.ITypeReference, int> awaiterMapOpt,
-            ILambdaSyntaxHelper lambdaSyntaxHelper)
+            LambdaSyntaxFacts lambdaSyntaxFacts)
         {
             Debug.Assert(symbolMap != null);
             Debug.Assert(previousTopLevelMethod != null);
@@ -69,7 +69,7 @@ internal sealed class EncVariableSlotAllocator : VariableSlotAllocator
             _awaiterMapOpt = awaiterMapOpt;
             _lambdaMapOpt = lambdaMapOpt;
             _closureMapOpt = closureMapOpt;
-            _lambdaSyntaxHelper = lambdaSyntaxHelper;
+            _lambdaSyntaxFacts = lambdaSyntaxFacts;
 
             // Create a map from local info to slot.
             var previousLocalInfoToSlot = new Dictionary<EncLocalInfo, int>();
@@ -254,7 +254,7 @@ private bool TryGetPreviousLambdaSyntaxOffset(SyntaxNode lambdaOrLambdaBodySynta
             // Syntax map contains mapping for lambdas, but not their bodies. 
             // Map the lambda first and then determine the corresponding body.
             var currentLambdaSyntax = isLambdaBody 
-                ? _lambdaSyntaxHelper.GetLambda(lambdaOrLambdaBodySyntax) 
+                ? _lambdaSyntaxFacts.GetLambda(lambdaOrLambdaBodySyntax) 
                 : lambdaOrLambdaBodySyntax;
 
             // no syntax map 
@@ -271,7 +271,7 @@ private bool TryGetPreviousLambdaSyntaxOffset(SyntaxNode lambdaOrLambdaBodySynta
             SyntaxNode previousSyntax;
             if (isLambdaBody)
             {
-                previousSyntax = _lambdaSyntaxHelper.TryGetCorrespondingLambdaBody(previousLambdaSyntax, lambdaOrLambdaBodySyntax);
+                previousSyntax = _lambdaSyntaxFacts.TryGetCorrespondingLambdaBody(previousLambdaSyntax, lambdaOrLambdaBodySyntax);
                 if (previousSyntax == null)
                 {
                     previousSyntaxOffset = 0;

src/Compilers/Core/Portable/Emit/EditAndContinue/ILambdaHelper.cs → src/Compilers/Core/Portable/Emit/EditAndContinue/LambdaSyntaxFacts.cs

@@ -2,9 +2,9 @@
 
 namespace Microsoft.CodeAnalysis.Emit
 {
-    internal interface ILambdaSyntaxHelper
+    internal abstract class LambdaSyntaxFacts
     {
-        SyntaxNode GetLambda(SyntaxNode lambdaOrLambdaBodySyntax);
+        public abstract SyntaxNode GetLambda(SyntaxNode lambdaOrLambdaBodySyntax);
 
         /// <summary>
         /// When invoked on a node that represents an anonymous function or a query clause [1]
@@ -14,6 +14,6 @@ internal interface ILambdaSyntaxHelper
         /// E.g. join clause declares left expression and right expression -- each of these expressions is a lambda body.
         /// JoinClause1.GetCorrespondingLambdaBody(JoinClause2.RightExpression) returns JoinClause1.RightExpression.
         /// </summary>
-        SyntaxNode TryGetCorrespondingLambdaBody(SyntaxNode previousLambdaSyntax, SyntaxNode lambdaOrLambdaBodySyntax);
+        public abstract SyntaxNode TryGetCorrespondingLambdaBody(SyntaxNode previousLambdaSyntax, SyntaxNode lambdaOrLambdaBodySyntax);
     }
 }
\ No newline at end of file

src/Compilers/VisualBasic/Portable/BasicCodeAnalysis.vbproj

@@ -350,7 +350,7 @@
     <Compile Include="Emit\EditAndContinue\VisualBasicDefinitionMap.vb" />
     <Compile Include="Emit\EditAndContinue\EmitHelpers.vb" />
     <Compile Include="Emit\EditAndContinue\PEDeltaAssemblyBuilder.vb" />
-    <Compile Include="Emit\EditAndContinue\VisualBasicLambdaSyntaxHelper.vb" />
+    <Compile Include="Emit\EditAndContinue\VisualBasicLambdaSyntaxFacts.vb" />
     <Compile Include="Emit\EditAndContinue\VisualBasicSymbolMatcher.vb" />
     <Compile Include="Emit\EventSymbolAdapter.vb" />
     <Compile Include="Emit\FieldSymbolAdapter.vb" />

src/Compilers/VisualBasic/Portable/Emit/EditAndContinue/VisualBasicDefinitionMap.vb

@@ -37,8 +37,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Emit
             End Get
         End Property
 
-        Protected Overrides Function GetLambdaSyntaxHelper() As ILambdaSyntaxHelper
-            Return VisualBasicLambdaSyntaxHelper.Instance
+        Protected Overrides Function GetLambdaSyntaxFacts() As LambdaSyntaxFacts
+            Return VisualBasicLambdaSyntaxFacts.Instance
         End Function
 
         Friend Function TryGetAnonymousTypeName(template As NamedTypeSymbol, <Out> ByRef name As String, <Out> ByRef index As Integer) As Boolean

src/Compilers/VisualBasic/Portable/Emit/EditAndContinue/VisualBasicLambdaSyntaxHelper.vb → src/Compilers/VisualBasic/Portable/Emit/EditAndContinue/VisualBasicLambdaSyntaxFacts.vb

@@ -3,19 +3,19 @@
 Imports Microsoft.CodeAnalysis.Emit
 
 Namespace Microsoft.CodeAnalysis.VisualBasic.Emit
-    Friend Class VisualBasicLambdaSyntaxHelper
-        Implements ILambdaSyntaxHelper
+    Friend Class VisualBasicLambdaSyntaxFacts
+        Inherits LambdaSyntaxFacts
 
-        Public Shared ReadOnly Instance As ILambdaSyntaxHelper = New VisualBasicLambdaSyntaxHelper()
+        Public Shared ReadOnly Instance As LambdaSyntaxFacts = New VisualBasicLambdaSyntaxFacts()
 
         Private Sub New()
         End Sub
 
-        Public Function GetLambda(lambdaOrLambdaBodySyntax As SyntaxNode) As SyntaxNode Implements ILambdaSyntaxHelper.GetLambda
+        Public Overrides Function GetLambda(lambdaOrLambdaBodySyntax As SyntaxNode) As SyntaxNode
             Return LambdaUtilities.GetLambda(lambdaOrLambdaBodySyntax)
         End Function
 
-        Public Function TryGetCorrespondingLambdaBody(previousLambdaSyntax As SyntaxNode, lambdaOrLambdaBodySyntax As SyntaxNode) As SyntaxNode Implements ILambdaSyntaxHelper.TryGetCorrespondingLambdaBody
+        Public Overrides Function TryGetCorrespondingLambdaBody(previousLambdaSyntax As SyntaxNode, lambdaOrLambdaBodySyntax As SyntaxNode) As SyntaxNode
             Return LambdaUtilities.GetCorrespondingLambdaBody(lambdaOrLambdaBodySyntax, previousLambdaSyntax)
         End Function
     End Class